1. Field of the Invention
The present invention relates to a failure detection device for the spindle head of a machine tool including a plurality of sensors.
2. Description of the Related Art
A machine tool can machine a workpiece into a desired shape by moving a spindle head relative to the workpiece. The spindle head includes a spindle for holding a tool and a spindle motor for rotating the spindle. The spindle motor is driven so as to rotate the tool around an axis. The spindle head has a bearing that rotatably supports the spindle and the shaft of the spindle motor. Moreover, the spindle motor has an oil seal that prevents coolant from entering between the shaft and the case of the spindle motor. The bearing and the oil seal deteriorate over time by using the spindle head. The bearing and the oil seal may become defective due to the entry of foreign matters thereinto.
In the related art, it is known that a temperature sensor, a vibration sensor, etc., is disposed in a machine tool and abnormality of the machine tool is detected (For example, see WO2016/133100 and Japanese Unexamined Patent Publication No. 2011-60076). Furthermore, it is known that a humidity sensor or a gas sensor is disposed instead of the temperature sensor or the like so as to detect the failure of a bearing (For example, see Japanese Unexamined Patent Publication No. 2016-131004).